Switch actuating mechanism (momentary type) for pin-plunger type electrical switch



May 21, 1968 A. POCH 3,

SWITCH ACTUATING ME NISM (MOMENTARY TYPE) FOR NGE SWITCH PIN-FLU R TYPE B TRI 1 ed Nov. 19

INVENTOR ALFRED B. POCH BY A TORNEY United States Patent 3,384,725 SWITCH ACTUATING MECHANISM (MOMENTARY TYPE) FOR PIN-PLUNGER TYPE ELECTRICAL SWITCH Alfred B. Poch, St. Paul, Minn., assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed Nov. 23, 1966, Ser. No. 596,523 6 Claims. (Cl. 200-153) ABSTRACT OF THE DISCLOSURE This invention which is the property of the Spenry Rand Corporation is directed to a mechanism which may be attached to a precision switch of the pin-plunger type such as disclosed in the McGall Patent 1,960,020 for obtaining a momentary actuation thereof which is substantially independent of the time that the manual switching force is applied. Specifically, the invention comprises a housing which may be molded or otherwise formed so as to contain a closed track or raceway in which is located a plurality of rollers. Communicating with the raceway are first and second apertures. The first aperture is designed to accommodate one of the roller members and is positioned to be in contact with the pin-plunger of the aforementioned switch. Located in the second aperture is a plunger which when depressed, forces the roller members to advance along the track and in doing so to momentarily depress the pin-plunger of the electrical switch.

Prior art mechanisms for obtaining momentary actuation of electrical switches use magnets, deflection pawls, overriding friction springs, detent-pressure releases, etc. all of which involve numerous parts, excessive friction and wear, complicated linkages, etc. with attendant high cost. The present invention uses commonly available rollers which, for example, may be ball bearings, positioned in a relatively inexpensive housing. The use of numerous rollers reduces the wear on the actuator parts by a factor equal to the number of rollers employed. Hence, the actuator of this invention is highly reliable over an extremely large number of cycles of operation.

For a better understanding of the construction and op eration of the switch actuator device of this invention, reference is made to the following drawings in which:

FIGURE 1 illustrates a partially cross sectioned view of the switch actuator mechanism of this invention, and

FIGURES 2a through illustrate schematically the operation of the actuator mechanism.

Referring now to FIGURE 1, there is shown a pinplunger type switch indicated generally by the numeral 2 having a pin-plunger 4 adapted to be depressed by a switch arm 6 which is pivotally mounted to the switch body 8 at pivot point 10. The type of switch for which r the actuator mechanism of this invention is best suited is commonly referred to in the art as a microswitch. Since the internal workings of the switch 2 form no part of the present invention, it is believed unnecessary to describe in detail the functioning of the various parts contained therein. It is believed sufiicient to point out that the electrical contacts contained within the body member 8 are moved or actuated by the depression and release of the spring biased pin-plunger 4.

The present invention is designed as an attachment for the switch 2 for obtaining a momentary actuation of the electrical switch the time period of which is independent to a large degree from the time that a switching force is applied to the assembly. To accomplish this purpose, the-re is provided a housing 12 which may be molded or otherwise formed from plastic, metal or other suitable material and which is adapted to be secured to the switch 2 by adhesive bonding or other suitable means. In the bottom end 16 of the housing 12 is a hollowed out portion 18 which permits the switch 2 to be fully contained within the boundaries of the housing 12.

Formed within the housing 12 is a cavity 20, here shown as a circular track or raceway about a central raised projection 22. Communicating with the cavity 20 is a first aperture 24 and a second aperture 26. Located within the track 20 are a plurality of roller members 28 which may take the form of spherical balls or cylindrical rollers depending upon the design chosen for the raceway 20. One of the roller members 30 is located in the first aperture 24 and, as 'will be later shown, remains in this location during the operation of the switch mechanism. To prevent the roller member 30 contained in aperture 24 from dropping out of the desired position when the switch lever arm 6 is moved downward, the housing 12 is provided with a lip 32 at the bottom of the aperture 24. This lip constricts the aperture 24 to a diameter or dimension slightly less than the diameter of the roller member 30. The diameter of the aperture 24 is such that the roller member 30 is constrained to move only in a vertical direction. The location of the aperture 24 and its length is such that the roller member 30 rests against the switch arm '6 and extends into the raceway 20 when the switch 2 is in its unactuated position. Of course, it is not essential that the switch 2 have an arm 6. The roller member 30 can be made to cooperate directly with the pin plunger 4.

Located within the second aperture 26 is a plunger 34 having a first portion 36 which is adapted to enter into the track or raceway 20 upon the manual or mechanical depression of the end portion 38 which extends outwardly from the top surface 14 of the housing 21.

Between the portions 36 and 38 of the plunger 34 is a shoulder 40 which is designed to provide a stop for a return spring 42. The other end of the return spring 42 rests against a second shoulder 44 formed by a reduction in the diameter of the aperture 26.

Operation The operation of the switch actuating mechanism can best be obtained by noting the schematic mechanical drawings of FIGURES 2a through 20. As the plunger 34 moves downward, it forces the roller members a and b along the raceway 24. Roller b forces roller c downward, thus rotating the switch lever arm 6 to depress the pinplunger 4 and actuate the contacts in the switch member 2. The maximum downward rotation of the switch arm 6 occurs when the roller members b and c are aligned as shown in FIGURE 2a. It should be noted, however, that the plunger member 34 has not, as yet, reached its maxi mum depression into the raceway 20. Accordingly, as the plunger 34 continues its downward movement, roller b pushing rollers d, e and f ahead of it, moves into the lefthand portion of the raceway 20. As is shown in FIGURE 2b, with the plunger 34 at its maximum depression, the return spring contained within the switch 2 forces the lever arm 6 upward lifting the roller c into its normal position which is as illustrated in FIGURE 1. Thus it can be seen that the movement of the plunger 34 does not interfere with the switch return action, since the roller members do not return to their original starting position. After the switching force is removed from the plunger 34, the return spring 42 (FIGURE 1) lifts the plunger 34 causing the roller 1 to fall against roller a which is the initial position of the parts prior to the actuation of the plunger 34. This condition is illustrated in FIGURE 20.

The scope of the invention should not be restricted to the precise configuration illustrated in FIGURE 1. Many variations, including, but not limited to raceway configurations other than circular, fewer or more rollers, longer, shorter or no switch lever at all, more than one plunger member 34, and accordingly movement of the rollers in either a clockwise or a counter clockwise direction, will become apparent to those skilled in the art after reading this specification. Accordingly, it is to be understood that the foregoing disclosure relates to only preferred embodiments of the invention and numerous modifications and alterations may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A device for obtaining a momentary actuation of an electrical switch substantially independent of the time that a switching force is applied comprising:

v(a) a pin-plunger type electrical switch having a set of contacts movable from a first to a second position in response to the depression of said pin-plunger (b) a housing adapted to be secured to said switch, said housing having a cavity therein forming a track and first and second apertures communicating with said track, said first aperture being in cooperative relationship with said pin-plunger.

(c) a plurality of roller members positioned in said track and at least one of said rollers being positioned in said first aperture for imparting motion to said pin-plunger and extending partially into said cavity when said set of contacts are in said first position, and

(d) a means located in said second aperture for moving said rollers along said track upon the application of a switching force thereto.

2. The device as in claim 1 wherein said housing comprises:

(a) a block of material having a top, bottom and four sides with a cavity therein forming a circular raceway about an integrally formed post,

(b) a first aperture formed in the bottom surface thereof communicating with said circular raceway having a slightly greater width than the diameter of said roller members, and

(c) a second aperture formed in the top surface of said block communicating with said raceway at a position out of vertical alignment with said first aperture.

3. The device as in claim 1 wherein said roller members comprise a spherically shaped material of a diameter slightly less than the width of said track.

4. The device as in claim 1 wherein said last-mentioned means comprises a plun er movably secured in said second aperture having a first end extending from said housing and a second end adapted to extend into said cavity to advance said roller members along said track upon application of a switching force to said first end.

5. Apparatus as in claim 4 and further including a return spring positioned within said second aperture and engaging said plunger for urging said plunger out of said cavity upon removal of said switching force.

6. The device as in claim 1 wherein said roller members comprise cylind-rically shaped material of a diameter slightly less than the width of said track and of a length slightly less than the depth of said track.

References Cited FOREIGN PATENTS 163,372 10/1933 Switzerland.

ROBERT K. SCHAEFER, Primary Examiner. H. BURKS, Assistant Examiner. 

